View full sizeMotoya Nakamura/ The OregonianThomas Kaye, retired businessman and amateur scientist, talks about the likely flight path of a hijacked Boeing 727 and where D.B. Cooper's body should have been found if he died from his risky nighttime jump. He spoke from a lectern draped with a large parachute at a Cooper symposium Saturday.

Notorious Northwest skyjacker D.B. Cooper likely knew what he was doing when he chose to jump out of an Boeing 727 wearing a nonmaneuverable military backpack, and he almost certainly survived his 10,000-foot drop into a dark patch of southern Washington 40 years ago.

The session drew more than 100 people, ranging from people directly involved in the search to those with just a passing knowledge of the case that has riveted Pacific Northwesterners for decades. Its stars were the co-called sleuths, many with specialized professional qualifications as well as an abiding curiosity about a man who jumped from the sky with $200,000 in cash on Nov. 24, 1971, and has never been found.

Although the collective brainpower at the symposium did not solve the case, Cooper snoopers expressed optimism the case will be solved -- perhaps soon.

Some of the biggest revelations or most controversial assertions Saturday include:

Although very few Americans knew it, U.S.-backed planes delivering supplies in Thailand repeatedly dropped parachutists safely from Boeing 727s flying with their rear door open and aft stairway down, just as Cooper demanded his plane be flown from Seattle to Reno, said Mark Metzler, an engineer, aircraft aficionado and expert skydiver. Separately, Boeing, maker of the aircraft, had compiled more than 10,000 pages documenting the safety of flying the plane that way, he said.

When Cooper bought his $20 Portland-to-Seattle ticket that day, he asked the agent: "This is a 727, right?"

Cooper, after demanding he be provided four parachutes when the plane stopped in Seattle, made an expert choice of which to use, raising the likelihood he landed alive, Metzler said.

FBI investigators have said Cooper's chute choice showed he was clueless, suggesting he died on impact.

But Metzler said Cooper was right to select the extremely strong military chute, not a sleeker luxury sport chute that would have allowed him to steer his path. The C9 chute is the "pit bull of all chutes" and by taking the jumper down straight, rather than allowing him to blindly steer into a cliff or mountainside in the dark, "allows you to land alive," he said.

Metzler showed footage of what happened to other jumpers who parachuted from a 727’s rear stairs: The chute opens directly behind the jumper in a rather gentle way, smoothly slowing him to near-zero forward motion, before rising over the person and allowing him to fall downward.

From the way D.B. Cooper modeled himself on cartoon Dan Cooper, including dressing in a black suit, drinking bourbon and smuggling a fake bomb onto a plane inside an attache case, it appears the hijacker closely identified with the cartoon hero, Abraczinskas said. That means the hijacker almost certainly could read French, she said.

The fact that the cartoon was sold in Cananda but not the U.S. is one of several signs suggesting D.B. Cooper came from Canada or had another Canadian connection, said Thomas Kaye, a retired businessman and amateur scientist who has read the FBI files on the case.

The fact Ingram found the cash there rules out the possibility that Cooper landed in a lake or another submerged location where he could have died on impact but not left his large, probably white, parachute to reveal the location to searchers, Kaye said.

That also suggests Cooper -- or, more likely, someone else -- buried the money in the sand bar after the crime, he said.

View full sizeMotoya Nakamura/ The OregonianA program for the symposium lies on a chair at a conference room at the Hilton Hotel in downtown Portland. Asked by a frightened flight attendant whether he bore a grudge against Northwest Orient Airlines, the man calling himself Dan Cooper said no, famously adding: âI just have a grudge."